Hybrid solar panel

ABSTRACT

Disclosed is an apparatus and method for improved efficiency in the collection of solar energy, in which an energy conversion device is provided that includes a first zone for converting received solar energy into thermal energy, the first zone having a Fresnel lens, and a heat absorption layer with heat collectors embedded therein. The energy conversion device also includes a second zone positioned at a lower level of first energy zone for converting received solar energy into electrical energy utilizing a photovoltaic cell.

PRIORITY

This application claims priority to U.S. Provisional Application No.60/997,861, filed Oct. 5, 2007, and to U.S. Provisional Application No.60/982,559, filed Oct. 25, 2007, the contents of each of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Conventional photovoltaic (PV) panels generate electrical energydirectly. Conventional concentrated solar thermal power (CSP) plantsextract heat energy from sunlight, but require a separate apparatus toutilize the heat energy, such as a Rankine-cycle plant to convert theheat energy into the electrical energy. CSP plants, which employ hugearrays of mirrors to concentrate solar energy, are centralizedpowerplants, which do not have the flexibility and modularity of PVpanels. Although the CSP conversion is generally more efficient than useof photovoltaic panels, the recent development of concentrated solarphotovoltaic (CPV) cells matches the CSP conversion efficiency of lightenergy into power.

CPV can operate at more than twice the efficiency than non-concentratedPV cells. CPV's also reduce the amount of required PV cell material,which is the most expensive part of a solar panel. However, CPV's onlyconvert direct sunlight and waste approximately half of the availableenergy in diffuse sunlight.

Importantly, the photovoltaic conversion efficiency depends on theconcentration factor and the temperature of PV cells; higher efficiencyis obtained at higher concentration factor and lower PV celltemperature. Concentration method of CPV enables creating separate zonesof different temperatures in a solar panel.

The present invention overcomes the shortcoming of losing diffusesunlight in conventional solar concentration technologies by providing ahybrid solar panel (HSP) design that captures diffuse sunlight and atthe same time creates two temperature zones within the panel, providingrooftop CPV's harnessing heat and power, both usable in buildingapplications. CPV technology represents a step forward on the issue ofconversion efficiency and at the same time the issue of cost ofconventional PV technology. The present invention further improves CPVtechnology and provides a technological foundation for a zero energybuilding with the potential of decreasing the nation's total housingenergy consumption.

SUMMARY OF THE INVENTION

The hybrid solar panel of the present invention overcomes theshortcomings of conventional systems by converting direct sunlight intoelectricity and collecting the unconverted direct sunlight and thediffuse sunlight as heat in a single solar panel.

In the present invention, an energy conversion device and method areprovided that include a refractive lens, a heat absorption layercontaining a plurality of heat collectors, a plurality of insulators, afirst zone positioned between and including the lens and heat absorptionlayer for converting received solar energy into thermal energy, whereinthe first zone includes the plurality of insulators, and a second zoneis positioned between the plurality of insulators for convertingreceived solar energy into electrical energy.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 shows direct sunlight entering into the a single collector of theenergy conversion device 100 of the present invention;

FIG. 2 provides an enlarged view of a photovoltaic zone of FIG. 1; and

FIG. 3 shows diffuse insolation of sunlight onto a collector surface ofa plurality of collectors at an upward zero-angle position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description of preferred embodiments of theinvention will be made in reference to the accompanying drawings. Indescribing the invention, explanation about related functions orconstructions known in the art are omitted for the sake of clearness inunderstanding the concept of the invention, to avoid obscuring theinvention with unnecessary detail.

The present invention provides a hybrid energy conversion device formaximizing the amount of energy extracted from solar power. In apreferred embodiment, the apparatus of a preferred embodiment of thepresent invention includes, as shown in FIGS. 1-3, a first zone 102 forconverting received solar energy into thermal energy and a second zone204 for converting received solar energy into electrical energy. FIG. 1shows direct sunlight entering into the energy conversion device 100 ofthe present invention and FIG. 3 shows a plurality of collectors of thepresent invention arranged side by side to provide an extended lightcollecting surface.

In a preferred embodiment of the present invention, an upper boundary isprovided of the first zone 102, with the upper boundary preferablyprovided by a refractive Fresnel lens 110 that focuses the sunlight ontothe PV zone 240. A heat absorption layer 130 and Fresnel lens 110 definethe first zone 102.

In a preferred embodiment, the first zone 102 is occupied by ambientair, with the Fresnel lens forming a boundary of a double-layeredexterior cover, evacuated to operate in a vacuum.

In an alternate embodiment, heat absorption layer 130 and a collectorside 152 of the hybrid energy conversion device are curved to form areflective mirror to direct sunlight onto photovoltaic (PV) zone 240,which acts as a collector of electric power via operation of a PV cell241 therein.

The heat absorption layer 130 contains a plurality of heat collectors136, preferably pipes filled with fluid that flows through and absorbssolar energy. In a preferred embodiment, once heated by the solar power,the fluid leaves the first zone 102 where the heat is removed frombefore the fluid returns to the plurality of heat collectors 136. Itwill be appreciated that the heat collectors 136 may also be heat pipes,within which fluid forms a closed loop for transport of absorbed solarenergy to a condenser-end.

A plurality of insulators 149 thermally protect the PV zone 240 from theheat absorption layer 130. To maximize the operational efficiency of thePV 241, the PV zone 240 includes upper and lower conduits 242 and 246provide air coolant and water coolant 244 and 248, respectively. Thecover of 242 is 243, which in a preferred embodiment are made of opticalmaterials configured to block long wavelength radiation.

A receiving area of the hybrid solar panel is preferably made of smallareas of high-performance PV cells, which convert radiation energy intoelectrical power, surrounded by larger areas of radiative absorbing andheat conducting surfaces, which convert radiation energy into heat anddistribute the heat. The solar panel includes thermal management unitand heat transporting elements, as well as the control (both thermallyfor temperature controls and dynamically for tracking control. It willbe recognized that the whole hybrid energy conversion panel can bemounted onto an arm that tracks the movement of the sun, either in oneor two dimensions. Alternatively, each individual collector within apanel can be tracked to follow the movement of the sun.

While the invention has been shown and described with reference tocertain exemplary embodiments of the present invention thereof, it willbe understood by those skilled in the art that various changes in formand details may be made therein without departing from the spirit andscope of the present invention as defined by the appended claims andequivalents thereof.

1. An energy conversion device comprising: a refractive lens; a heatabsorption layer containing a plurality of heat collectors; a pluralityof insulators; a first zone positioned between and including the lensand heat absorption layer, the first zone for converting received solarenergy into thermal energy, wherein the first zone includes theplurality of insulators; and a second zone is positioned between theplurality of insulators, the second zone for converting received solarenergy into electrical energy.
 2. The device of claim 1, wherein thesecond zone is thermally cooled.
 3. The device of claim 1, wherein theplurality of insulators of the second zone consist of two insulatorspositioned on opposite sides of a photovoltaic cell.
 4. The device ofclaim 1, wherein the lens is a Fresnel lens.
 5. The device of claim 1,further comprising a one-axis tracking device.
 6. The device of claim 1,further comprising a two-axis tracking device.
 7. The device of claim 3,wherein a plurality of the energy conversion devices adjacently housedin a panel, including a double-layered cover having a vacuum betweenlayers thereof.
 8. The device of claim 1, wherein the heat collectorsare heat pipes.
 9. The device of claim 1, wherein the second zone isconditioned with water coolant in a lower conduit and air coolant in anupper conduit.
 10. The device of claim 1, wherein the upper conduitincludes an optical cover to block infrared radiation.
 11. The device ofclaim 1, wherein the first zone operates in a vacuum.
 12. A method forenergy conversion, the method comprising: diffracting sunlight in arefractive lens; absorbing, in a heat absorption layer containing aplurality of heat collectors, solar heat; within a first zone positionedbetween and including the lens and heat absorption layer, convertingreceived solar energy into thermal energy, wherein the first zoneincludes the plurality of insulators; and within a second zonepositioned between the plurality of insulators, converting receivedsolar energy into electrical energy.